1. Field of the Invention
This invention relates to a miniature circuit breaker, and more particularly, to a molded case with a barrier member in both the base and in the cover which separates the inner cavity from the aperture area containing a handle part for manual operation of the circuit breaker.
2. Background Information
Present designs for a molded case for a miniature circuit breaker take various forms for forming and accommodating the handle part of a circuit breaker mechanism. Several of these designs provide coring for an arcuate area on the inner surface of both the base and the cover near an aperture for a handle, which aperture is in the peripheral walls of the case, and which walls and aperture are part of ribbing systems of the base and the cover. The walls form a cavity for carrying a circuit breaker mechanism. The arcuate coring area in both the base and in the cover corresponds to the surface and shape of a rounded end portion of the handle such that each side of the handle fits into and is supported by one of these arcuate areas in a manner that the handle projects from the aperture and is easily moved into its various positionings during operation of the circuit breaker mechanism.
Some of these present molded case designs for a miniature circuit breaker may include a barrier member in at least the cover, and a barrier member on the handle relative to the base, but these designs are more suitable for circuit breakers which have an overall thickness of about 1.000 inch. These present day designs for a barrier member prove to be inadequate for circuit breakers having an overall thickness of about 0.500 inches. If used in the thinner circuit breakers, a wide clearance may exist between the aperture for the handle and the main cavity, creating an unsafe condition especially when a short circuit occurs and an arc is formed in the cavity where the arc and associated gases can escape from the handle aperture.
There remains a need, therefore, for an improved case design for a miniature circuit breaker which minimizes the clearances in the handle aperture and which optimizes the safety factor for miniature circuit breakers.